A tubular skylight is a long cylindrical skylight that reflects sunlight indoors without the heat gain or loss of an ordinary skylight. Tubular skylights are an excellent form of alternative lighting that bring diffuse natural light into dark areas of a home or office. In addition to the free daytime operation, they may qualify for local tax credits as an energy conservation device. They cost much less than standard, framed skylights and are generally straightforward to install. Some tubuluar skylights are available that include either an incandescent or fluorescent bulb inside the light tube, which is wired to the wall switch. Others, for use in a bathroom, come with integrated exhaust system.